View MAX9985ETX_732408.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-0705 Rev 0; 1/07
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch
General Description
The MAX9985 high-linearity, dual-channel downconversion mixer is designed to provide approximately 6dB gain, +28.5dBm of IIP3, and 10.5dB of noise figure (NF) ideal for diversity receiver applications. With a 700MHz to 1000MHz RF frequency range and a 570MHz to 865MHz LO frequency range, this mixer is ideal for lowside LO injection architectures. In addition, the broad frequency range makes the MAX9985 ideal for GSM 850/950, 2G/2.5G EDGE, WCDMA, cdma2000(R), and iDEN(R) base-station applications. The MAX9985 dual-channel downconverter achieves a high level of component integration. The MAX9985 integrates two double-balanced active mixer cores, two LO buffers, a dual-input LO selectable switch, and a pair of differential IF output amplifiers. In addition, integrated on-chip baluns at the RF and LO ports allow for singleended RF and single-ended LO inputs. The MAX9985 requires a typical 0dBm LO drive. Supply current is adjustable up to 400mA. The MAX9985 is available in a 36-pin thin QFN package (6mm x 6mm) with an exposed paddle. Electrical performance is guaranteed over the extended temperature range, from TC = -40C to +85C.
Features
o 700MHz to 1000MHz RF Frequency Range o 570MHz to 865MHz LO Frequency Range o 50MHz to 250MHz IF Frequency Range o 6dB Typical Conversion Gain o 10.5dB Typical Noise Figure o +28.5dBm Typical Input IP3 o +16.2dBm Typical Input 1dB Compression Point o 77dBc Typical 2RF-2LO Spurious Rejection at PRF = -10dBm o Dual Channels Ideal for Diversity Receiver Applications o 47dB Typical Channel-to-Channel Isolation o -3dBm to +3dBm LO Drive o Integrated LO Buffer o Internal RF and LO Baluns for Single-Ended Inputs o Built-In SPDT LO Switch with 43dB LO1-to-LO2 Isolation and 50ns Switching Time o Pin-Compatible with MAX9995/MAX9995A 1700MHz to 2200MHz Mixers o Lead-Free Package Available
MAX9985
Applications
850MHz WCDMA Base Stations GSM 850/GSM 950, 2G/2.5G EDGE Base Stations cdmaOneTM and cdma2000 Base Stations iDEN Base Stations Fixed Broadband Wireless Access Wireless Local Loop Private Mobile Radios Military Systems Digital and Spread-Spectrum Communication Systems Microwave Links
cdma2000 is a registered trademark of Telecommunications Industry Association. iDEN is a registered trademark of Motorola, Inc. cdmaOne is a trademark of CDMA Development Group.
Ordering Information
PART MAX9985ETX TEMP RANGE -40C to +85C PIN-PACKAGE PKG CODE
36 Thin QFN-EP* T3666-2 (6mm x 6mm) 36 Thin QFN-EP* (6mm x 6mm), T3666-2 T/R 36 Thin QFN-EP* (6mm x 6mm), T3666-2 lead free, bulk 36 Thin QFN-EP* (6mm x 6mm), T3666-2 lead free, T/R
MAX9985ETX-T
-40C to +85C
MAX9985ETX+
-40C to +85C
MAX9985ETX+T
-40C to +85C
*EP = Exposed paddle.
T = Tape-and-reel package.
+Denotes lead-free and RoHS compliant.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch MAX9985
ABSOLUTE MAXIMUM RATINGS
VCC to GND ...........................................................-0.3V to +5.5V LO1, LO2 to GND ...............................................................0.3V Any Other Pins to GND...............................-0.3V to (VCC + 0.3V) RFMAIN, RFDIV, and LO_ Input Power ..........................+20dBm RFMAIN, RFDIV Current (RF is DC shorted to GND through balun) ...............................................................................50mA Continuous Power Dissipation (TC = +70C) (Note A) 36-Pin Thin QFN (derate 26mW/C above +70C) .........10.8W Operating Temperature Range ...........................-40C to +85C Maximum Junction Temperature Range..........................+150C JA .................................................................................+38C/W JC ...................................................................................7.4C/W Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
Note A: TC is the temperature on the exposed paddle of the package.
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(Using the Typical Application Circuit, no input RF or LO signals applied, VCC = 4.75V to 5.25V, TC = -40C to +85C. Typical values are at VCC = 5.0V, TC = +25C, unless otherwise noted.)
PARAMETER Supply Voltage SYMBOL VCC Total supply current (see Table 1 for lower current settings) Supply Current ICC VCC (pin 16) VCC (pin 30) IFM+/IFM- (total of both) IFD+/IFD- (total of both) LOSEL Input High Voltage LOSEL Input Low Voltage LOSEL Input Current VIH VIL IIH and IIL -10 2 0.8 +10 CONDITIONS MIN 4.75 TYP 5 400 80 80 105 105 V V A MAX 5.25 440 mA UNITS V
AC ELECTRICAL CHARACTERISTICS
(Using the Typical Application Circuit, VCC = 4.75V to 5.25V, RF and LO ports are driven from 50 sources, PLO = -3dBm to +3dBm, PRF = -5dBm, fRF = 820MHz to 920MHz, fLO = 670MHz to 865MHz, fIF = 100MHz, fRF > fLO, TC = -40C to +85C. Typical values are at VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, fRF = 870MHz, fLO = 770MHz, fIF = 100MHz, TC = +25C, unless otherwise noted.) (Note 1)
PARAMETER RF Frequency LO Frequency IF Frequency LO Drive Conversion Gain Gain Variation over Temperature Flatness over any one of three frequency bands: fRF = 824MHz to 849MHz fRF = 869MHz to 894MHz fRF = 880MHz to 915MHz SYMBOL fRF fLO fIF PLO GC (Note 2) (Note 2) IF matching components affect the IF frequency range (Note 2) (Note 3) (Note 6) CONDITIONS MIN 700 570 50 -3 4.5 6 -0.012 TYP MAX 1000 865 250 +3 7.5 UNITS MHz MHz MHz dBm dB dB/C
Conversion Gain Flatness
0.1
dB
2
_______________________________________________________________________________________
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch
AC ELECTRICAL CHARACTERISTICS (continued)
(Using the Typical Application Circuit, VCC = 4.75V to 5.25V, RF and LO ports are driven from 50 sources, PLO = -3dBm to +3dBm, PRF = -5dBm, fRF = 820MHz to 920MHz, fLO = 670MHz to 865MHz, fIF = 100MHz, fRF > fLO, TC = -40C to +85C. Typical values are at VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, fRF = 870MHz, fLO = 770MHz, fIF = 100MHz, TC = +25C, unless otherwise noted.) (Note 1)
PARAMETER Noise Figure, Single Sideband Noise Figure under Blocking Condition Input Compression Point Output Compression Point Small-Signal Compression under Blocking Conditions Third-Order Input Intercept Point Third-Order Input Intercept Point Variation over Temperature Third-Order Output Intercept Point OIP3 PRF = -5dBm/tone, fIF = 100MHz, fRF1-fRF2 = 1MHz (Note 3) fRF = 870MHz, fLO PRF = -10dBm = 770MHz, fSPUR = PRF = -5dBm 820MHz (Note 3) fRF = 870MHz, fLO PRF = -10dBm = 770MHz, fSPUR = 803.3MHz (Note 3) PRF = -5dBm PLO1 = +3dBm, PLO2 = +3dBm, fLO1-fLO2 = 1MHz, PRF = -5dBm, fIF = 100MHz (Notes 3, 5) 32.0 63 58 70 60 IIP3 P1dB OP1dB PRF = -5dBm, fRF = PBLOCKER = +8dBm 870MHz, fBLOCKER PBLOCKER = +11dBm = 871MHz fRF1-fRF2 = 1MHz, fIF = 100MHz, PRF = -5dBm/tone 18.5 SYMBOL NF CONDITIONS fIF = 190MHz, no blockers present (Note 3) +11dBm blocker tone applied to RF port at 961MHz, fRF = 860MHz, fLO = 670MHz, fIFDESIRED = 190MHz, fBLOCKER = 291MHz (Notes 3, 4) MIN TYP 10.5 MAX 13 UNITS dB
MAX9985
21
26
dB
16.2 21.2 0.1
dBm dBm dB
0.25 28.5 -0.01 34.5 77 dBc 72 85 dBc 75 dBm dB/C dBm
2RF-2LO Spur
2x2
3RF-3LO Spur
3x3
LO1-to-LO2 Port Isolation Maximum LO Leakage at RF Port Maximum 2LO Leakage at RF Port Maximum LO Leakage at IF Port Minimum RF-to-IF Isolation Minimum Channel-to-Channel Isolation
39
43 -40 -45 -30 -30 -20 -20
dB dBm dBm dBm dB
30 PRF = -10dBm, RFMAIN (RFDIV) power measured at IFDIV (IFMAIN), relative to IFMAIN (IFDIV), all unused ports terminated to 50
45
40
47
dB
_______________________________________________________________________________________
3
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch MAX9985
AC ELECTRICAL CHARACTERISTICS (continued)
(Using the Typical Application Circuit, VCC = 4.75V to 5.25V, RF and LO ports are driven from 50 sources, PLO = -3dBm to +3dBm, PRF = -5dBm, fRF = 820MHz to 920MHz, fLO = 670MHz to 865MHz, fIF = 100MHz, fRF > fLO, TC = -40C to +85C. Typical values are at VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, fRF = 870MHz, fLO = 770MHz, fIF = 100MHz, TC = +25C, unless otherwise noted.) (Note 1)
PARAMETER LO Switching Time RF Input Impedance LO Input Impedance IF Output Impedance RF Input Return Loss LO Input Return Loss IF Return Loss Differential LO on and IF terminated LO port selected LO port unselected RF terminated in 50 SYMBOL CONDITIONS 50% of LOSEL to IF settled within 2 degrees (Note 3) MIN TYP 0.05 50 50 200 24 35 36 20 MAX 1 UNITS s dB dB dB
Note 1: All limits reflect losses of external components. Output measurements taken at IF outputs of the Typical Application Circuit. Note 2: Performance is guaranteed for fRF = 820MHz to 920MHz, fLO = 670MHz to 865MHz, and fIF = 100MHz. Operation outside this range is possible, but with degraded performance of some parameters. See the Typical Operating Characteristics. Note 3: Guaranteed by design and characterization. Note 4: Measured with external LO source noise filtered so the noise floor is -174dBm/Hz. This specification reflects the effects of all SNR degradations in the mixer including the LO noise, as defined in Maxim Application Note 2021. Note 5: Measured at IF port at IF frequency. LOSEL may be in any logic state. Note 6: Performance at TC = -40C is guaranteed by design.
4
_______________________________________________________________________________________
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch
Typical Operating Characteristics
(Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25C, unless otherwise noted.)
CONVERSION GAIN vs. RF FREQUENCY
TC = -30C CONVERSION GAIN (dB) 7
MAX9985 toc01
MAX9985
CONVERSION GAIN vs. RF FREQUENCY
MAX9985 toc02
CONVERSION GAIN vs. RF FREQUENCY
MAX9985 toc03
8
8
8
CONVERSION GAIN (dB)
6
6 PLO = -3dBm, 0dBm, +3dBm 5
CONVERSION GAIN (dB)
7
7
6 VCC = 4.75V, 5.0V, 5.25V 5
5
TC = +85C
TC = +25C
4 700 800 900 1000 RF FREQUENCY (MHz)
4 700 800 900 1000 RF FREQUENCY (MHz)
4 700 800 900 1000 RF FREQUENCY (MHz)
INPUT IP3 vs. RF FREQUENCY
MAX9985 toc04
INPUT IP3 vs. RF FREQUENCY
MAX9985 toc05
INPUT IP3 vs. RF FREQUENCY
VCC = 4.75V VCC = 5.0V
MAX9985 toc06
30 29 INPUT IP3 (dBm) 28 27 26 25 24 700 800 900 TC = +25C TC = +85C
30 29 INPUT IP3 (dBm) 28 27 PLO = -3dBm, 0dBm, +3dBm 26 25 24
30 29 INPUT IP3 (dBm) 28 27 26 25 24 VCC = 5.25V
TC = -30C
1000
700
800
900
1000
700
800
900
1000
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
NOISE FIGURE vs. RF FREQUENCY
MAX9985 toc07
NOISE FIGURE vs. RF FREQUENCY
MAX9985 toc08
NOISE FIGURE vs. RF FREQUENCY
MAX9985 toc09
14 13 NOISE FIGURE (dB) 12 11 10 9 8 7 700 800 900 TC = -30C TC = +25C TC = +85C
14 13 NOISE FIGURE (dB) 12 11 10 9 8 7 PLO = -3dBm, 0dBm, +3dBm
14 13 NOISE FIGURE (dB) 12 11 10 9 8 7 VCC = 5.0V VCC = 4.75V VCC = 5.25V
1000
700
800
900
1000
700
800
900
1000
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
_______________________________________________________________________________________
5
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch MAX9985
Typical Operating Characteristics (continued)
(Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25C, unless otherwise noted.)
2RF-2LO RESPONSE vs. RF FREQUENCY
MAX9985 toc10
2RF-2LO RESPONSE vs. RF FREQUENCY
PLO = +3dBm PRF = -5dBm
MAX9985 toc11
2RF-2LO RESPONSE vs. RF FREQUENCY
PRF = -5dBm
MAX9985 toc12 MAX9985 toc18 MAX9985 toc15
80 75 2RF-2LO RESPONSE (dBc) 70
TC = +85C
PRF = -5dBm
80 75 2RF-2LO RESPONSE (dBc) 70
80 75 2RF-2LO RESPONSE (dBc) 70
TC = -30C 65 60 55 50 700 800 900 1000 RF FREQUENCY (MHz) TC = +25C
PLO = -3dBm 65 60 55 50 700 800 900 1000 RF FREQUENCY (MHz) PLO = 0dBm
VCC = 4.75V, 5.0V, 5.25V 65 60 55 50 700 800 900 1000 RF FREQUENCY (MHz)
3RF-3LO RESPONSE vs. RF FREQUENCY
MAX9985 toc13
3RF-3LO RESPONSE vs. RF FREQUENCY
PRF = -5dBm
MAX9985 toc14
3RF-3LO RESPONSE vs. RF FREQUENCY
95 PRF = -5dBm VCC = 5.0V
95 TC = +25C 3RF-3LO RESPONSE (dBc) 85
PRF = -5dBm TC = +85C
95
3RF-3LO RESPONSE (dBc)
3RF-3LO RESPONSE (dBc)
85
85
VCC = 4.75V
75 TC = -30C 65
75 PLO = -3dBm, 0dBm, +3dBm 65
75 VCC = 5.25V 65
55 700 800 900 1000 RF FREQUENCY (MHz)
55 700 800 900 1000 RF FREQUENCY (MHz)
55 700 800 900 1000 RF FREQUENCY (MHz)
INPUT P1dB vs. RF FREQUENCY
MAX9985 toc16
INPUT P1dB vs. RF FREQUENCY
MAX9985 toc17
INPUT P1dB vs. RF FREQUENCY
19 18 INPUT P1dB (dBm) 17 16 VCC = 5.0V 15 14 13 VCC = 4.75V VCC = 5.25V
19 18 TC = +85C INPUT P1dB (dBm) 17 16 15 14 13 700 800 900 1000 1100 TC = -30C TC = +25C
19 18 INPUT P1dB (dBm) 17 16 PLO = -3dBm, 0dBm, +3dBm 15 14 13
1200
700
800
900
1000
1100
1200
700
800
900
1000
1100
1200
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
6
_______________________________________________________________________________________
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch
Typical Operating Characteristics (continued)
(Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25C, unless otherwise noted.)
CHANNEL ISOLATION vs. RF FREQUENCY
MAX9985 toc19
MAX9985
CHANNEL ISOLATION vs. RF FREQUENCY
MAX9985 toc20
CHANNEL ISOLATION vs. RF FREQUENCY
MAX9985 toc21
60 55 CHANNEL ISOLATION (dB) 50 45 TC = -30C, +25C, +85C 40 35 30 700 800 900
60 55 CHANNEL ISOLATION (dB) 50 45 PLO = -3dBm, 0dBm, +3dBm 40 35 30
60 55 CHANNEL ISOLATION (dB) 50 45 VCC = 4.75V, 5.0V, 5.25V 40 35 30
1000
700
800
900
1000
700
800
900
1000
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
LO LEAKAGE AT IF PORT vs. LO FREQUENCY
MAX9985 toc22
LO LEAKAGE AT IF PORT vs. LO FREQUENCY
MAX9985 toc23
LO LEAKAGE AT IF PORT vs. LO FREQUENCY
MAX9985 toc24
-10 -15 -20 -25 -30 TC = +85C -35 -40 600 650 700 750 800 850 TC = +25C TC = -30C
-10 -15 -20 PLO = 0dBm -25 -30 -35 PLO = -3dBm -40 PLO = +3dBm
-10 -15 -20 VCC = 5.25V -25 -30 VCC = 4.75V -35 -40 VCC = 5.0V
LO LEAKAGE AT IF PORT (dBm)
LO LEAKAGE AT IF PORT (dBm)
LO LEAKAGE AT IF PORT (dBm)
900
600
650
700
750
800
850
900
600
650
700
750
800
850
900
LO FREQUENCY (MHz)
LO FREQUENCY (MHz)
LO FREQUENCY (MHz)
RF-TO-IF ISOLATION vs. RF FREQUENCY
MAX9985 toc25
RF-TO-IF ISOLATION vs. RF FREQUENCY
MAX9985 toc26
RF-TO-IF ISOLATION vs. RF FREQUENCY
MAX9985 toc27
60 55 RF-TO-IF ISOLATION (dB) TC = +85C 50 45 40 TC = -30C 35 30 700 800 900 TC = +25C
60 55 RF-TO-IF ISOLATION (dB) 50 45 40 35 30
60 55 RF-TO-IF ISOLATION (dB) 50 45 40 35 30 VCC = 4.75V, 5.0V, 5.25V
PLO = -3dBm, 0dBm, +3dBm
1000
700
800
900
1000
700
800
900
1000
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
_______________________________________________________________________________________
7
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch MAX9985
Typical Operating Characteristics (continued)
(Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25C, unless otherwise noted.)
LO LEAKAGE AT RF PORT vs. LO FREQUENCY
MAX9985 toc28
LO LEAKAGE AT RF PORT vs. LO FREQUENCY
MAX9985 toc29
LO LEAKAGE AT RF PORT vs. LO FREQUENCY
MAX9985 toc30
-20 LO LEAKAGE AT RF PORT (dBm)
-20 LO LEAKAGE AT RF PORT (dBm)
-20 LO LEAKAGE AT RF PORT (dBm)
-30 TC = +25C -40 TC = -30C
-30
-30
-40
-40 VCC = 4.75V, 5.0V, 5.25V -50
-50
TC = +85C
-50
PLO = -3dBm, 0dBm, +3dBm
-60 500 600 700 800 900 1000 1100 1200 LO FREQUENCY (MHz)
-60 500 600 700 800 900 1000 1100 1200 LO FREQUENCY (MHz)
-60 500 600 700 800 900 1000 1100 1200 LO FREQUENCY (MHz)
2LO LEAKAGE AT RF PORT vs. LO FREQUENCY
MAX9985 toc31
2LO LEAKAGE AT RF PORT vs. LO FREQUENCY
MAX9985 toc32
2LO LEAKAGE AT RF PORT vs. LO FREQUENCY
MAX9985 toc33
-10 2LO LEAKAGE AT RF PORT (dBm)
-10 2LO LEAKAGE AT RF PORT (dBm)
-10 2LO LEAKAGE AT RF PORT (dBm)
-20
TC = +25C
-20
PLO = 0dBm
-20
-30 TC = +85C -40
-30 PLO = -3dBm -40
-30
-40 VCC = 4.75V, 5.0V, 5.25V
-50 TC = -30C -60 500 600 700 800 900 1000 1100 1200 LO FREQUENCY (MHz)
-50 PLO = +3dBm -60 500 600 700 800 900 1000 1100 1200 LO FREQUENCY (MHz)
-50
-60 500 600 700 800 900 1000 1100 1200 LO FREQUENCY (MHz)
LO SWITCH ISOLATION vs. RF FREQUENCY
MAX9985 toc34
LO SWITCH ISOLATION vs. RF FREQUENCY
MAX9985 toc35
LO SWITCH ISOLATION vs. RF FREQUENCY
MAX9985 toc36
50 TC = -30C 45
50
50
LO SWITCH ISOLATION (dB)
LO SWITCH ISOLATION (dB)
LO SWITCH ISOLATION (dB)
45
45
40 TC = +85C 35 TC = +25C
40 PLO = -3dBm, 0dBm, 3dBm 35
40 VCC = 4.75V, 5.0V, 5.25V 35
30 600 700 800 900 1000 1100 1200 RF FREQUENCY (MHz)
30 600 700 800 900 1000 1100 1200 RF FREQUENCY (MHz)
30 600 700 800 900 1000 1100 1200 RF FREQUENCY (MHz)
8
_______________________________________________________________________________________
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch
Typical Operating Characteristics (continued)
(Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25C, unless otherwise noted.)
RF PORT RETURN LOSS vs. RF FREQUENCY
MAX9985 toc37
MAX9985
IF PORT RETURN LOSS vs. IF FREQUENCY
MAX9985 toc38
LO SELECTED RETURN LOSS vs. LO FREQUENCY
MAX9985 toc39
0 5 10 15 20 25 30 500 600 700 800 900 PLO = -3dBm, 0dBm, +3dBm
0 5 IF PORT RETURN LOSS (dB) 10 15 20 25 30 VCC = 4.75V, 5.0V, 5.25V
0 LO SELECTED RETURN LOSS (dB)
RF PORT RETURN LOSS (dB)
10 PLO = +3dBm 20 PLO = 0dBm 30
40
PLO = -3dBm
50 0 100 200 300 400 500 500 600 700 800 900 1000 1100 1200 IF FREQUENCY (MHz) LO FREQUENCY (MHz)
1000 1100 1200
RF FREQUENCY (MHz)
LO UNSELECTED RETURN LOSS vs. LO FREQUENCY
LO UNSELECTED RETURN LOSS (dB)
MAX9985 toc40
SUPPLY CURRENT vs. TEMPERATURE (TC)
420 SUPPLY CURRENT (mA) 410 400 390 380 370 VCC = 4.75V
MAX9985 toc41
CONVERSION GAIN vs. RF FREQUENCY (VARIOUS LO AND IF BUFFER BIAS)
MAX9985 toc42
0
430 VCC = 5.25V VCC = 5.0V
7.0
10
CONVERSION GAIN (dB)
1 6.5
5
6
0
4
2
3
20 PLO = -3dBm, 0dBm, +3dBm 30
6.0 7 8, 9 SEE TABLE 1 FOR R1, R2, AND ICC VALUES. 700 800 900 1000
40
50 500 600 700 800 900 1000 1100 1200 LO FREQUENCY (MHz)
360 -35 -15 5 25 45 65 85 TEMPERATURE (C)
5.5
RF FREQUENCY (MHz)
INPUT IP3 vs. RF FREQUENCY (VARIOUS LO AND IF BUFFER BIAS)
MAX9985 toc43
2RF-2LO RESPONSE vs. RF FREQUENCY (VARIOUS LO AND IF BUFFER BIAS)
MAX9985 toc44
3RF-3LO RESPONSE vs. RF FREQUENCY (VARIOUS LO AND IF BUFFER BIAS)
PRF = -5dBm 6 0 2 3 1
MAX9985 toc45
30 29 28 INPUT IP3 (dBm) 27 26 25 24 23 22 21 20 9 8 7 6 5 3 0 1 2 4
85 PRF = -5dBm 2RF-2LO RESPONSE (dBc) 80 0 2 3 6
90 85 3RF-3LO RESPONSE (dBc) 80 75 70 65
75
70 5 8 60 7
5
4 8 7
65
9 60 55
SEE TABLE 1 FOR R1, R2, AND ICC VALUES. 700 800 900 1000
SEE TABLE 1 FOR R1, R2, AND ICC VALUES. 700 800 900 1000
SEE TABLE 1 FOR R1, R2, AND ICC VALUES. 700 800 900 1000
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
RF FREQUENCY (MHz)
_______________________________________________________________________________________
9
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch MAX9985
Typical Operating Characteristics (continued)
(Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25C, unless otherwise noted.) INPUT P1dB vs. RF FREQUENCY RF-TO-IF ISOLATION vs. RF FREQUENCY LO LEAKAGE AT IF PORT vs. LO FREQUENCY (VARIOUS LO AND IF BUFFER BIAS) (VARIOUS VALUES OF L3 AND L6) (VARIOUS VALUES OF L3 AND L6)
MAX9985 toc46
17 16 INPUT P1dB (dBm) 15 14 13 12 11 10 9 8 7, 8, 9 4, 5, 6 1, 2, 3
0
MAX9985 toc47
LO LEAKAGE AT IF PORT (dBm)
-15 -20 -25 -30 L = 30nH -35 -40 600 650
L = 15nH RF-TO-IF ISOLATION (dB) 60 L = 30nH 50
0 L = 7.5nH
40 L = 7.5nH 30 0 20 700 800 900 1000
L = 15nH
SEE TABLE 1 FOR R1, R2, AND ICC VALUES. 700 800 900 1000 700 750 800 850 900
RF FREQUENCY (MHz)
LO FREQUENCY (MHz)
RF FREQUENCY (MHz)
Table 1. DC Current vs. Bias Resistor Settings
BIAS CONDITION 0 1 2 3 4 5 6 7 8 9 DC CURRENT (mA) 397.8 345.0 316.5 297.5 301.2 271.7 252.2 260.1 230.5 211.5 R1 AND R4 VALUES () 1070 1400 1400 1400 1910 1910 1910 2800 2800 2800 R2 AND R5 VALUES () 1100 1100 1620 2210 1100 1620 2210 1100 1620 2210
10
______________________________________________________________________________________
MAX9985 toc48
18
-10
70
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch
Pin Description
PIN 1 2 3, 5, 7, 12, 20, 22, 24, 25, 26, 34 4, 6, 10, 16, 21, 30, 36 8 9 11 NAME RFMAIN TAPMAIN GND FUNCTION Main Channel RF input. Internally matched to 50. Requires an input DC-blocking capacitor. Main Channel Balun Center Tap. Bypass to GND with capacitors close to the pin. Ground Power Supply. Connect bypass capacitors as close to the pin as possible (see the Typical Application Circuit). Diversity Channel Balun Center Tap. Bypass to GND with capacitors close to the pin. Diversity Channel RF Input. Internally matched to 50. Requires an input DC-blocking capacitor. IF Diversity Amplifier Bias Control. Connect a 1.07k resistor from this pin to ground to set the bias current for the diversity IF amplifier (see the Typical Operating Characteristics for typical performance versus resistor value). Diversity Mixer Differential IF Output. Connect pullup inductors from each of these pins to VCC (see the Typical Application Circuit). Connect a 30nH inductor from this pin to ground to increase the RF-to-IF and LO-to-IF isolation. Connect this pin to ground if isolations can be degraded (see the Typical Operating Characteristics for typical degradation). LO Diversity Amplifier Bias Control. Connect a 1.1k resistor from this pin to ground to set the bias current for the diversity LO amplifier (see the Typical Operating Characteristics for typical performance versus resistor value). No Connection. Not internally connected. Local Oscillator 1 Input. This input is internally matched to 50. Requires an input DC-blocking capacitor. Local Oscillator Select. Set this pin to high to select LO1. Set low to select LO2. Local Oscillator 2 Input. This input is internally matched to 50. Requires an input DC-blocking capacitor. LO Main Amplifier Bias Control. Connect a 1.1k resistor from this pin to ground to set the bias current for the main LO amplifier (see the Typical Operating Characteristics for typical performance versus resistor value). Connect a 30nH inductor from this pin to ground to increase the RF-IF and LO-IF isolation. Connect this pin to ground if isolations can be degraded (see the Typical Operating Characteristics for typical degradation). Main Mixer Differential IF Output. Connect pullup inductors from each of these pins to VCC (see the Typical Application Circuit). IF Main Amplifier Bias Control. Connect a 1.07k resistor from this pin to ground to set the bias current for the main IF amplifier (see the Typical Operating Characteristics for typical performance vs. resistor value). Exposed Paddle. Solder the exposed paddle to the ground plane using multiple vias. This paddle affects RF performance and provides heat dissipation.
MAX9985
VCC TAPDIV RFDIV IFDBIAS
13, 14
IFD+, IFD-
15
LEXTD
17 18, 28 19 23 27 29
LODBIAS N.C. LO1 LOSEL LO2 LOMBIAS
31
LEXTM
32, 33 35 --
IFM-, IFM+ IFMBIAS EP
______________________________________________________________________________________
11
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch MAX9985
Detailed Description
The MAX9985 is a dual-channel downconverter designed to provide 6dB of conversion gain, +28.5dBm input IP3, and +16.2dBm 1dB input compression point, with a 10.5dB NF. In addition to its high-linearity performance, the MAX9985 achieves a high level of component integration. The device integrates two double-balanced active mixers for two-channel downconversion. Both the main and diversity channels include a balun and matching circuitry to allow 50 single-ended interfaces to the RF ports and the two LO ports. An integrated single-pole, double-throw (SPDT) switch provides 50ns switching time between the two LO inputs with 43dB of LO-to-LO isolation and a -40dBm of LO leakage at the RF port. Furthermore, the integrated LO buffers provide a high drive level to each mixer core, reducing the LO drive required at the MAX9985's inputs to a -3dBm to +3dBm range. The IF ports for both channels incorporate differential outputs for downconversion, which is ideal for providing enhanced IIP2 performance. Dual-channel downconversion makes the MAX9985 ideal for diversity receiver applications. In addition, specifications are guaranteed over broad frequency ranges to allow for use in GSM 850/950, 2G/2.5G EDGE, WCDMA, cdma2000, and iDEN base stations. The MAX9985 is specified to operate over a 700MHz to 1000MHz RF input range, a 570MHz to 865MHz LO range, and a 50MHz to 250MHz IF range. The external IF components set the lower frequency range (see the Typical Operating Characteristics for details). (LOSEL), where logic-high selects LO1 and logic-low selects LO2. LO1 and LO2 inputs are internally matched to 50, requiring only an 82pF DC-blocking capacitor. To avoid damage to the part, voltage MUST be applied to VCC before digital logic is applied to LOSEL. Alternatively, a 1k resistor can be placed in series at the LOSEL to limit the input current in applications where LOSEL is applied before VCC. The main and diversity channels incorporate a twostage LO buffer that allows for a wide-input power range for the LO drive. All guaranteed specifications are for an LO signal power from -3dBm to +3dBm. The on-chip low-loss baluns, along with LO buffers, drive the double-balanced mixers. All interfacing and matching components from the LO inputs to the IF outputs are integrated on-chip.
High-Linearity Mixer
The core of the MAX9985 dual-channel downconverter consists of two double-balanced, high-performance passive mixers. Exceptional linearity is provided by the large LO swing from the on-chip LO buffers. When combined with the integrated IF amplifiers, the cascaded IIP3, 2RF-2LO rejection, and NF performance are typically +28.5dBm, 77dBc, and 10.5dB, respectively.
Differential IF
The MAX9985 has a 50MHz to 250MHz IF frequency range, where the low-end frequency depends on the frequency response of the external IF components. Note that these differential ports are ideal for providing enhanced IIP2 performance. Single-ended IF applications require a 4:1 (impedance ratio) balun to transform the 200 differential IF impedance to a 50 singleended system. After the balun, the IF return loss is better than 20dB. The user can use a differential IF amplifier on the mixer IF ports, but a DC block is required on both IFD+/IFD- and IFM+/IFM- ports to keep external DC from entering the IF ports of the mixer.
RF Port and Balun
The RF input ports to both the main and diversity channels are internally matched to 50, requiring no external matching components. A DC-blocking capacitor is required as the input is internally DC-shorted to ground through the on-chip balun. The RF port return loss is typically 15dB over the entire 700MHz to 1000MHz RF frequency range.
Applications Information
Input and Output Matching
The RF and LO inputs are internally matched to 50. No matching components are required. Return loss at the RF port is typically 15dB over the entire input range and return loss at the LO ports are typically 25dB. RF and LO inputs require only DC-blocking capacitors for interfacing. The IF output impedance is 200 (differential). For evaluation, an external low-loss 4:1 (impedance ratio) balun transforms this impedance to a 50 single-ended output (see the Typical Application Circuit).
LO Inputs, Buffer, and Balun
The MAX9985 is optimized for a 570MHz to 865MHz LO frequency range. As an added feature, the MAX9985 includes an internal LO SPDT switch for use in frequency-hopping applications. The switch selects one of the two single-ended LO ports, allowing the external oscillator to settle on a particular frequency before it is switched in. LO switching time is typically less than 50ns, which is more than adequate for typical GSM applications. If frequency hopping is not employed, simply set the switch to either of the LO inputs. The switch is controlled by a digital input
12
______________________________________________________________________________________
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch
LO Buffer Bias Resistors
Bias currents for the two on-chip LO buffers is optimized by fine-tuning the off-chip resistors on LODBIAS (pin 17) and LOMBIAS (pin 29). The current in the buffer amplifiers is reduced by increasing the value of these resistors, but performance may degrade. See the Typical Operating Characteristics for key performance parameters versus this resistor value. Doubling the value of these resistors reduces the total chip current by approximately 50mA (see Table 1).
Power-Supply Bypassing
Proper voltage-supply bypassing is essential for highfrequency circuit stability. Bypass each VCC pin and TAPMAIN/TAPDIV with the capacitors shown in the Typical Application Circuit (see Table 2 for component values). Place the TAPMAIN/TAPDIV bypass capacitor to ground within 100 mils of the pin.
MAX9985
Table 2. Component Values
COMPONENT VALUE 39pF 0.033F -- 0.01F 150pF 82pF 560nH 30nH 1.07k 1.1k 0 4:1 -- DESCRIPTION Microwave capacitors (0402) Microwave capacitors (0603) Not used Microwave capacitors (0402) Microwave capacitors (0603) Microwave capacitors (0402) Wire-wound high-Q inductors (0805) Wire-wound high-Q inductors (0603) 1% resistors (0402) 1% resistors (0402) Resistors (1206) Transformers (200:50) Mini-Circuits TC4-1W-7A MAX9985 IC C1, C2, C7, C8 C3, C6 C4, C5 C9, C13, C15, C17, C18 C10, C11, C12, C19, C20, C21 C14, C16 L1, L2, L4, L5
IF Amplifier Bias Resistors
Bias currents for the two on-chip IF amplifiers are optimized by fine-tuning the off-chip resistors on IFDBIAS (pin 11) and IFMBIAS (pin 35). The current in the IF amplifiers is decreased by raising the value of these resistors, but performance may degrade. See the Typical Operating Characteristics for key performance parameters versus this resistor value. Doubling the value of this resistor reduces the current in each IF amplifier from 100mA to approximately 50mA (see Table 1).
LEXT Inductor
Short LEXT_ to ground using a 0 resistor. For applications requiring improved RF-to-IF and LO-to-IF isolation, LEXT_ can be used by connecting a low-ESR inductor from LEXT_ to GND. See the Typical Operating Characteristics on RF-to-IF port isolation and LO-to-IF port leakage for various inductor values. The load impedance presented to the mixer must be such that any capacitance from both IF- and IF+ to ground do not exceed several picofarads to ensure stable operating conditions. Approximately 100mA flows through LEXT_, so it is important to use a low-DCR wire-wound inductor.
L3, L6 R1, R4 R2, R5 R3, R6 T1, T2 U1
Exposed Paddle RF/Thermal Considerations
The exposed paddle (EP) of the MAX9985's 36-pin thin QFN-EP package provides a low thermal-resistance path to the die. It is important that the PCB on which the MAX9985 is mounted be designed to conduct heat from the EP. In addition, provide the EP with a lowinductance path to electrical ground. The EP MUST be soldered to a ground plane on the PCB, either directly or through an array of plated via holes.
Layout Considerations
A properly designed PCB is an essential part of any RF/microwave circuit. Keep RF signal lines as short as possible to reduce losses, radiation, and inductance. For the best performance, route the ground pin traces directly to the exposed paddle under the package. The PCB exposed paddle MUST be connected to the ground plane of the PCB. It is suggested that multiple vias be used to connect this paddle to the lower-level ground planes. This method provides a good RF/thermal-conduction path for the device. Solder the exposed paddle on the bottom of the device package to the PCB. Refer to the MAX9985 Evaluation Kit as a reference for board layout. Gerber files are available upon request at www.maxim-ic.com.
______________________________________________________________________________________
13
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch MAX9985
Typical Application Circuit
C19
VCC
L1 R3 C21
T1
IF MAIN OUTPUT
L2 C20 VCC R1 C18 IFMBIAS IFM+ GND IFML3 LOMBIAS LEXTM C17
4:1
VCC
R2 N.C. 28 27 26 LO2 GND GND GND LOSEL GND VCC VCC GND LO1 C14 C15 LO SELECT C16 LO2 25 24 23 22 21 20 19
VCC
36 RF MAIN INPUT RFMAIN C1 TAPMAIN C3 C2 VCC VCC C4 VCC C5 C6 C7 GND VCC GND TAPDIV RFDIV C8 10 VCC GND 1 2
35
34
33
32
31
VCC 30
29
MAX9985
3 4 5 6 7 8 9 11 IFDBIAS 12 GND 13 IFD+ 14 IFD15 LEXTD 16 VCC 17 LODBIAS 18 N.C. R5 EXPOSED PADDLE
RF DIV INPUT
LO1
VCC R4 C9 C11 L6
VCC C13
VCC
L5 R6 C12
T2
L4 C10
4:1
IF DIV OUTPUT
14
______________________________________________________________________________________
Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch
Pin Configuration/Functional Diagram
MAX9985
TOP VIEW (with exposed paddle on the bottom of the package)
LOMBIAS 29
IFMBIAS
LEXTM
IFM+
IFM-
GND
36 RFMAIN TAPMAIN GND VCC GND VCC GND TAPDIV RFDIV 1 2
35
34
33
32
31
30
28 27 26 LO2 GND GND GND LOSEL GND VCC GND LO1
MAX9985
3 4 5 6 7 8 9 10 VCC 11 IFDBIAS 12 GND 13 IFD+ 14 IFD15 LEXTD 16 VCC 17 LODBIAS 18 N.C. EXPOSED PADDLE 25 24 23 22 21 20 19
THIN QFN 6mm x 6mm
Chip Information
PROCESS: SiGe BiCMOS
Package Information
For the latest package outline information, go to www.maxim-ic.com/packages.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15
(c) 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
CARDENAS
N.C.
VCC
VCC

▲Up To Search▲

Price & Availability of MAX9985ETX

	To Download MAX9985ETX Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .